Note: Descriptions are shown in the official language in which they were submitted.
CA 02566055 2006-11-08
DESCRIPTION
WIND TURBINE BLADE AND METHOD OF INSTALLING
THE WIND TURBINE BLADE ON TOWER
Technical Field
The present invention relates to a wind
turbine blade assembly and a method of installing the
same.
Background Art
Diversification of energy supply has been on
progress. As one of the energy supply systems, wind
turbine generation using natural energy has been known
from ancient times. As wind turbines, vertical axis
type wind turbines and horizontal axis wind turbines
are known. Many of the vertical axis type wind
turbines are sma1l type wind turbines, in which a
Darrieus type wind turbine and a straight blade
vertical axis type wind turbine are known. In the
horizontal axis wind turbines suitable for a large
scale of power generation, a three-blade type wind
turbine is a mainstream.
As the three-blade type wind turbine stated
above, a large-sized wind turbine with the diameter of
60m and more between a blade end and an opposite blade
end in a rotation state is on a practical operation.
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A wind turbine power generation apparatus includes a
wind turbine tower which is higher than the radius
length of the blade, a nacelle rotatably installed at
the top of the wind turbine tower, and a three-blade
assembly rotatably installed to the nacelle. The
three-blade assembly includes a rotor head rotatably
supported by the nacelle, and three rotating blades
installed to the rotor head in a pitch angle
adjustable manner. When the three-blade assembly is
installed to the nacelle, climbing cranes are employed
for the wind turbine tower so that the wind turbine
tower is built up from the ground to the height
direction successively, as disclosed in Japanese Laid
Open Patent Application (JP-A-Heisei 10-205429) . The
climbing cranes are also used for suspending the three
blades.
The mass of the three-blade assembly
exceeding 60 m is huge. It is important for
suppression of the increase of the construction cost
to suspend the three-blade assembly which was
integrally assembled, rather than to suspend each one
of the three blades. In the suspension of the three-
blade assembly, suppression of the rotational movement
around the center of gravity and installation of a
rotation plane formed by the three blades on a
substantially vertical plane are required in order to
avoid damages caused by contacts between the three-
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blade assembly and the wind turbine tower and to
provide operational safety.
A conventional construction method includes a
manual operation for suspending a suspension technique
such as a nylon sling to blades and a head in
suspending the three-blade assembly by a crane. A
slinging operation is conducted by a slinging skilled
worker for sling work in a high place and a skilled
work including an operation of adjusting the center of
gravity. Accordingly, suspension to eliminate the
skilled work as much as possible is required.
A construction method of a wind turbine power
generation apparatus related to the above carried-out
is disclosed in Japanese Laid Open Patent Application
(JP-A-Heisei 10-205428). In this conventional
example, the climbing crane is used. However blades
are installed to the nacelle. Similar techniques are
disclosed in Japane5e Laid Open Patent Applications
(JP-A-Heisei 10-205429, JP-A-Heisei 10-205430, and JP-
A-Heisei 11-82285).
Disclosure of Invention
An object of the present invention is to
provide a method for installing wind turbine blade
assembly in which suspension can be realized while
excluding the skilled work as much as possible, and to
provide a wind turbine blade assembly therefor.
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Another object of the present invention is to
provide wind turbine blade assembly in which safety
and high efficiency is realized, and an installing
method thereof on a tower.
In an aspect of the present invention, a
method of constructing a wind turbine, is achieved by
forming a blade assembly in which a plurality of
blades are attached to a rotor head; by attaching a
suspension structure to the rotor head; by lifting the
blade assembly through the suspension structure by a
first crane; and by installing the blade assembly to a
nacelle of a wind turbine tower.
Here, the attaching a suspension structure is
achieved by attaching eye plates to the rotor head;
and by fixing a suspension plate coupled with a
suspension ring wire to the eye plates. Thus, the
blade assembly can be suspended through the suspension
ring wire by the first crane.
Also, when the plurality of blades are three
blades, the attaching the eye plates to the rotor head
may be achieved by sticking the eye plate to a portion
of the rotor head on an opposite side to one of the
three blades.
Also, the eye plates may have a plurality of
protrusion sections with holes, respectively, and the
suspension plate may have a hole corresponding to the
holes. The fixing a suspension plate may be achieved
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by inserting a pin into the holes of the plurality of
protrusion sections and the hole of the suspension
plate; and by inserting a slip-off prevention pin into
the pin.
Also, the lifting the blade assembly may be
achieved by lifting the blade assembly through the
suspension ring by the suspension tool of the first
crane; and by lifting up an end of at least one of the
plurality of blades by a second crane until the blade
assembly is suspended to a predetermined height.
Also, the method may be achieved by further
hanging cables to ones of the plurality of blades
other than the blade whose end is suspended by the
second crane; and pulling the cables.
Also, the pulling may be achieved by pulling
the cables such that a rotation plane of the plurality
of blades is inclined to have a predetermined angle
with respect to a vertical plane. AT this time, the
method may be achieved by further removing the
suspension structure from the blade assembly after the
blade assembly is installed to the nacelle of the wind
turbine tower.
In another aspect of the present invention, a
wind turbine structure includes a plurality of blades;
a rotor header to which the plurality of blades are
attached; and a suspension structure attached to the
rotor header.
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It is preferable that the suspension
structure is detachable to the rotor header.
The suspension structure may include eye
plates attached to the rotor header and having a
plurality of protrusion sections with a plurality of
holes, respectively; a suspension plate having a hole
corresponding to the plurality of holes and fixed to
the eye plates; a pin inserted into the plurality of
holes of the plurality of protrusion sections and the
hole of the suspension plate to fix the suspension
plate and the eye plate; and the slip-off prevention
pin inserted into the pin. In this case, the
suspension structure may further include a suspension
wire rotatably coupled with the suspension plate and
used when the blade assembly is suspended.
Also, the eye plates are preferably installed
to the rotor header such that a rotation plane of the
plurality of blades is inclined by a predetermined
angle from a vertical plane.
Also, when the plurality of blades are three
blades, the eye plates are stuck to a portion of the
rotor head on an opposite side to one of the three
blades.
Brief Description of Drawings
Fig. 1 is a diagram showing a three-blade
assembly laid on a blade structure laid base;
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Fig. 2 is a front view showing a relationship
of angular positions of three blades;
Fig. 3 is a front view showing a suspension
structure installed to the three-blade assembly;
Fig. 4 is a side view of the suspension
structure shown in Fig. 3;
Fig. 5 is a top view of the suspension
structure shown in Fig. 3;
Fig. 6 is a diagram showing a method for
installing a wind turbine blade assembly according to
the present invention;
Fig. 7 is a diagram showing a first
suspension stage in the method for installing the wind
turbine blade assembly according to the present
invention;
Fig. 8 is a diagram showing a second
suspension stage in the method for installing the wind
turbine blade assembly according to the present
invention; and
Fig. 9 is a diagram showing a gravity vector
and the center of gravity which acts on three blades.
Beat Mode for Carrying Out the Invention
Hereinafter, a wind turbine blade assembly of
the present invention will be described in detail with
reference to the attached drawings.
Fig. 1 is a diagram showing a wind turbine
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blade assembly according to the first embodiment of
the present invention. As shown in Fig. 1, a three-
blade assembly 1 is laid on a three-blade assembly
laid base 2 installed on a horizontal ground of a wind
turbine installation place. The thzee-blade assembly
1 includes a rotor head 3 and three blades 4 (a first
blade 4-A, a second blade 4-B and a third blade 4-C).
The rotor head 3 and the three blades 4-A, 4-B and 4-C
are integrally assembled on the three-blade assembly
laid base 2 in advance. Base portions of the three
blades are respectively disposed in three portions of
the rotor head around the rotational axis so as to be
pitch adjustable. The positions of these three base
portions are shown as three angular positions of 0
degree, 120 degrees and 240 degrees with respect to a
standard angular position (0 degree) around the
rotational axis L as virtually shown in Fig. 2. A
suspension structure to be described below is
integrally attached to the rotor head 3 on the
position of 180 degrees.
Fig. 3 shows an initial assembly state in
which the three-blade assembly 1 is laid on the three-
blade assembly laid base 2 through a stabilizing stand
5. A suspension structure 6 as stated above is
installed to the rotor head 3 on the angular position
of 180 degrees which is a center angular position of
an angular direction between the second blade 4-B on
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the angular position of 120 degrees and the third
blade 4-C on the angular position of 240 degrees. The
suspension structure 6 includes eye plates 8 fixed to
the rotor head 3 and a suspension plate 9, in which
the eye plates 8 are attached or stuck in an outer
peripheral surface region 7 of the rotor head 3, as
shown in Fig. 4. The eye plates 8 include first and
second upstream side protruding portions 8-U1 and 8-
U2, and first and second downstream side protruding
portions 8-D1 and 8-D2.
As shown in Fig. 5, the suspension plate 9 is
interposed between the first and second upstream side
protruding portions 8-U1 and 8-U2, and the first and
second downstream side protruding portions 8-D1 and 8-
D2. Pin holes 11-1, 11-2 and 11-3 are formed in
corresponding positions of the first upstream side
protruding portion 8-U1, the second upstream side
protruding portion 8-U2 and the suspension plate 9. A
pin 12-U is inserted to penetrate the three pin holes
11-1, 11-2 and 11-3 for fixing the suspension plate 9
to the eye plates 8. Pin holes 12-1, 12-2 and 12-3
are also formed in corresponding positions of the
first downstream side protruding portion 8-D1, the
second downstream side protruding portion 8-D2 and the
suspension plate 9. A pin 12-D is inserted to
penetrate the three pin holes 12-1, 12-2 and 12-3 for
fixing the suspension plate 9 to the eye plates 8.
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The pins 12-U and 12-D do not slip off from upstream
side eye plates 8-U and downstream side eye plate 8-D
respectively by slip-off prevention pins 13-U and 13-
D. The pins 12-U and 12-D are prevented from falling
off from the suspension plate 9 by chains 14-iJ arid 14-
D.
A suspension fork 16 is rotatably connected
to a suspension axis 15 of the suspension plate 9. An
end portion of the suspension fork 16 is rotatably
connected to the suspension axis 15, and a suspension
ring wire 18 is passed through the suspension fork 16.
As shown in Fig. 3, a suspension tool 19 from a crane
(not shown) is passed through a ring section in an end
portion of the suspension ring wire 18.
Fig. 6 shows a method for installing a wind
turbine blade assembly according to the present
invention. A crane 23 is disposed in the vicinity of
a wind turbine tower 22. The crane 23 includes a
first inclined crane section 24 and a second inclined
crane section 25. An inclined angle of the first
inclined crane section 24 is adjustably sustained by
an inclined angle adjustment cable 26. An inclined
angle of the second inclined crane section 25 from the
first inclined crane section 24 is adjustably
sustained by an inclined angle adjustment cable 27.
The first blade 4-A is suspended by a first pulling
cable 28 using the first inclined crane section 24,
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and the second blade 4-B is suspended from the ground
by a second pulling cable 29. The third blade 4-C is
preferably suspended from the ground by a third
pulling cable 29 (see Fig. 7) The three blades 4-A,
4-B and 4-C are suspended by the three pulling cables
in a substantially stable state.
Fig. 7 shows a first suspension step. In a
providing step of Fig. 1 which is a previous step to a
step of Fig. 7, the three blades 4-A, 4-B and 4-C are
sustained on the laid base 2 in a substantially
horizontal state. The suspension structure 6 is
suspended by the second inclined crane section 25 via
the suspension ring wire 18. In this first suspension
step, the suspension fork 16 slowly stands up toward
the vertical direction from the horizontal direction
as shown in Fig. 4, while the weight of the first
blade 4-A which is not directed to the vertical
direction provides the first blade 4-A with a
rotational force around a suspension point P included
in the suspension axis 15 as shown in Fig. 9. In the
first suspension step in which the suspension point P
is not suspended to a height position corresponding to
the length of the first blade 4-A which is
substantially equivalent to a rotational radius of the
wind turbine blade assembly, a free end of the first
blade 4-A is suspended by the first pulling cable 28
because of a danger of being in contact with the
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ground E. The further pulling force is preferably
provided by another pulling cable 31. It is more
preferable to provide both or either one of the second
blades 4-B and 4-C with the pulling force by another
pulling cable (not shown) to suppress the rotation or
oscillation of the three-blade assembly as a whole.
Fig. 8 shows a second suspension step. It is
same as in the first suspension step in a point that
the suspension structure 6 is suspended by the
suspension tool 19. In this second suspension step,
the suspension fork 16 stands up in the substantially
vertical direction. An angle 8 between a reference
rotation plane S1 and a vertical plane S2 in the
rotating blades can be designed to become
substantially zero. The angle 9 can be easily made to
be zero by providing the first blade 4-A with the
pulling force by using the third pulling cable 31
fixed to the vicinity of the free end of the first
blade 4-A with manual power. The angle is designed
to be an angle which is not zero and sustained during
the installation, as described below. In the second
suspension step, as shown in Fig. 9, a synthetic force
(Fl + F2) between a first gravity vector Fl acting on
the third blade 4-C and a second gravity vector F2
acting on the socond blade 3-T; has the following
relationship with respect to a third gravity vector F'3
acting on the first blade 4-A.
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2 F3 = Fl + F2
The direction of the synthetic force (Fl +
F2) is equivalent to a direction of the third gravity
vector F3, and the synthetic force among the first
gravity vector Fl, the second gravity vector F2 and
the third gravity vector F3 acts on the center of
gravity G of the three-blade assembly 1 as a whole.
In such a balanced relationship, there is no rotation
force generated in the three-blade assembly 1. In
order to prevent the swinging of the three-blade
assembly 1 caused by wind, the above cables 28 and 29
are appropriately used.
The inclined angle of the second inclined
crane section 2 is further increased, and the top of
the second inclined crane section 25 is further
closely approached to the wind turbine tower 22, so
that a downstream side attachment surface 32 of the
rotor head 3 is coupled to an attachment surface 34 of
the nacelle 33.
In a conventional sling operation, fastened
cables are made asymmetrical even in the skilled work,
and it takes long time for stabilization of a position
of the center of gravity. Moreover, when the position
of the center of gravity is stabilized and the
rotational movement of the three blades is stopped,
the angle 8 between the reference rotation plane by
the three blades and the vertical plane is increased
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due to the asymmetry. In order to decrease the angle
6, the skilled workers are forced to repeat the sling
operations over and over again in a trial and error
manner.
In t,he present invention, the positions of
suspension points are defined by the suspension axis
so that a fulcrum of the suspension force acts as
the rotation axis and no asymmetrical force is
generated in the three-blade assembly 1 which receives
10 the suspension force. The suspension structure 6 is
simply assembled at a working spot only by insertion
of the pins 12, and simply disassembled only by
extraction of the pins 12. The eye plates 8 which are
attachable and detachable to the rotor head 3 can also
15 be simply removed.
The three-blade assembly 1 is thus installed
to the nacelle 33 as an integrated object in a single
suspending operation, and dismantled from the nacelle.
The attachment surface 34 is designed at a
nacelle angle a with respect to the vertical plane.
The above-mentioned angle 6 is adjusted to be
consistent with the nacelle angle a. The suspension
point P is shifted to a slightly distant position from
the nacelle 33 compared to the center of gravity G
which is designed to be substantially consistent with
the rotation axis as shown in Fig. 9. Through this
design, the reference rotation plane S1 is sustained
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to be in parallel with the attachment plane 34. It is
extremely difficult to bring the inclined angle 8 of
the reference rotation plane 51 of the blades 4
suspended by the crane to be consistent with the
design angle cc and to maintain the angle 0 in a fixed
state by the sling operation. However, according to
the present invention, the reference rotation plane of
the blades 4 as a large mass object is sustained in
the design angle a naturally and autonomously without
relying on a manual operation which is difficult due
to the gravity.
According to the wind turbine blade assembly
and the assembling method thereof in the present
invention, an operational efficiency to install the
wind turbine blade assembly of a large sized wind
turbine to a nacelle on a tower of the wind turbine
tower is significantly improved and the safety can be
secured.
